1. Field of the Invention
The present invention relates to a system for miter cutting, and more particularly, to a system for miter cutting that includes a device for modeling the angle of convergent surfaces and transposing the modeled angle to a miter saw for miter cutting through a slot defined on the miter saw.
2. Background of the Related Art
The primary function of a miter saw is to cut a piece of material (hereinafter also referred to as a “workpiece”) at a defined angle. Miter saws are most often used to prepare moldings or decorative trim to fit adjacent to surfaces that converge to form an angle, such as an inside or outside corner, so that the moldings or trim appear to follow along the surfaces continuously.
For practical reasons as well as aesthetics, the workpieces are fit to the convergent surfaces by cutting each of the workpieces at an angle which equals, as nearly as possible, one half of the angle formed at the convergence.
Most, if not all, miter saws have preset locking positions for various angles and setting the cutting angle is easily accomplished if the convergence angle corresponds with one of these positions. For example, virtually all miter saws have a preset position for 45 degrees to facilitate cutting workpieces to fit a 90 degree convergence angle.
However, the process becomes more difficult if the convergence angle does not correspond to an angle having a preset cutting position on the miter saw. This circumstance is encountered more often than not, especially throughout existing structures, such as residential homes and apartments.
In these circumstances, half the convergence angle must be measured and transferred to the miter saw in a way that enables the miter saw to be positioned for cutting each workpiece accordingly. Moreover, most moldings or trim are not of equidimensional design, in that they have a planar surface which opposes an ornamental surface and top and bottom edges which may differ in width. For such applications, the miter saw can be set so that a first workpiece is cut to half the convergent angle for the workpiece to be placed along a first convergent surface, but the miter saw must then be set to the inverse or mirror image of the first angle before cutting the second workpiece so that the second workpiece can be positioned along the second convergent surface with the correct orientation. Thus, the measured angle of convergence must be measured and/or transferred to the miter saw twice.
Some devices exist which can measure both internal and external existing angles in degrees, enabling the operator to set the miter saw to one half of that angle by using the saw's miter scale. Other devices duplicate the existing angle and provide a means for transferring one half of that angle to the workpiece by pencil, or scribe, enabling the operator to set the miter saw by visual reference to that line.
The primary problems associated with using such devices are that they are prone to inaccuracies, because, among other things, they involve one or more intermediate steps between the measurement of the existing angle and the setting of the miter saw, each of which is capable of introducing error.
U.S. Pat. No. 5,473,821 to DeMarco discloses a device that can model a convergence angle and transfer one half of that angle to a power miter saw, but only if the miter saw is manufactured to resemble the miter saw described by DeMarco (hereinafter also referred to as the “DeMarco miter saw”). The Demarco miter saw, as described in the '821 patent, deviates from standard power miter saws so much that it would be impossible to use the DeMarco angle-modeling device on miter saws which have not been specifically manufactured in accordance therewith. DeMarco does not demonstrate flaws in the standard power miter saw design or provide justification for changing manufacturing practices to produce miter saws as those shown in the '821 patent, and his design introduces a variety of problems not presented by the standard design.
For example, a workpiece placed on the DeMarco miter saw is held against a guide fence on only one side of the cut rather than both sides as it is with standard designs. This configuration decreases support for the workpiece and increases the possibility that it will move during the cutting process, thereby compromising accuracy, since the cutting action of the blade tends to move or bend the workpiece. The configuration also reduces the operator's options with regard to stabilizing the workpiece against the fence, thus creating safety issues which are not found in the standard design.
Another problem with the DeMarco design relates to the need to move the fences to duplicate the angel of convergence. This configuration increases the complexity and difficulty associated with using the DeMarco miter saw because it requires the reorientation of the workpiece, and any workpiece support system, for different angles and for mitering separate pieces to frame the same angle. In contrast, with the standard design the workpiece is always cut along the same axis, which generally corresponds to a workbench or other support system for the workpiece.
The DeMarco miter saw presents further difficulty in using it to frame an interior angle because each fence blocks the path of a workpiece placed against the other, thus eliminating the operators ability to make one cut for both dimension and angle.
Thus, there is a need for a device which overcomes the problems associated with the prior art as described above. In particular, what is needed is a system or device for modeling an angle formed by convergent surfaces and transferring one half of that angle directly to a miter saw, which can be employed with power miter saws of standard design and hand miter saws designed to accommodate it. Clearly, a device such as this would increase the speed, accuracy and efficiency of the miter saw and miter cutting process.